A final but related issue is the fact that the rates presented in this study were not adjusted for age. We recognize the importance of making age adjustments to correct for crude differences for an outcome resulting from different age distributions, particularly when the outcome is related to an increased probability of occurrence such as an increased risk of cancer among older age groups. However, making age adjustments for machinery incidents requires some type of exposure or prevalence estimates of machine operation by age. Given that this type of exposure data is not available, the crude rates presented in this study are likely the most beneficial measure of risk.